From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946442Ab2JDVev (ORCPT ); Thu, 4 Oct 2012 17:34:51 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:45983 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946377Ab2JDV1l (ORCPT ); Thu, 4 Oct 2012 17:27:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Larry Finger , "John W. Linville" Subject: [ 15/33] b43legacy: Fix crash on unload when firmware not available Date: Thu, 4 Oct 2012 14:26:37 -0700 Message-Id: <20121004210600.358137950@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.2.421.g261b511 In-Reply-To: <20121004210558.383865383@linuxfoundation.org> References: <20121004210558.383865383@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Larry Finger commit 2d838bb608e2d1f6cb4280e76748cb812dc822e7 upstream. When b43legacy is loaded without the firmware being available, a following unload generates a kernel NULL pointer dereference BUG as follows: [ 214.330789] BUG: unable to handle kernel NULL pointer dereference at 0000004c [ 214.330997] IP: [] drain_workqueue+0x15/0x170 [ 214.331179] *pde = 00000000 [ 214.331311] Oops: 0000 [#1] SMP [ 214.331471] Modules linked in: b43legacy(-) ssb pcmcia mac80211 cfg80211 af_packet mperf arc4 ppdev sr_mod cdrom sg shpchp yenta_socket pcmcia_rsrc pci_hotplug pcmcia_core battery parport_pc parport floppy container ac button edd autofs4 ohci_hcd ehci_hcd usbcore usb_common thermal processor scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh_alua scsi_dh fan thermal_sys hwmon ata_generic pata_ali libata [last unloaded: cfg80211] [ 214.333421] Pid: 3639, comm: modprobe Not tainted 3.6.0-rc6-wl+ #163 Source Technology VIC 9921/ALI Based Notebook [ 214.333580] EIP: 0060:[] EFLAGS: 00010246 CPU: 0 [ 214.333687] EIP is at drain_workqueue+0x15/0x170 [ 214.333788] EAX: c162ac40 EBX: cdfb8360 ECX: 0000002a EDX: 00002a2a [ 214.333890] ESI: 00000000 EDI: 00000000 EBP: cd767e7c ESP: cd767e5c [ 214.333957] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 214.333957] CR0: 8005003b CR2: 0000004c CR3: 0c96a000 CR4: 00000090 [ 214.333957] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 214.333957] DR6: ffff0ff0 DR7: 00000400 [ 214.333957] Process modprobe (pid: 3639, ti=cd766000 task=cf802e90 task.ti=cd766000) [ 214.333957] Stack: [ 214.333957] 00000292 cd767e74 c12c5e09 00000296 00000296 cdfb8360 cdfb9220 00000000 [ 214.333957] cd767e90 c104c4fd cdfb8360 cdfb9220 cd682800 cd767ea4 d0c10184 cd682800 [ 214.333957] cd767ea4 cba31064 cd767eb8 d0867908 cba31064 d087e09c cd96f034 cd767ec4 [ 214.333957] Call Trace: [ 214.333957] [] ? skb_dequeue+0x49/0x60 [ 214.333957] [] destroy_workqueue+0xd/0x150 [ 214.333957] [] ieee80211_unregister_hw+0xc4/0x100 [mac80211] [ 214.333957] [] b43legacy_remove+0x78/0x80 [b43legacy] [ 214.333957] [] ssb_device_remove+0x1d/0x30 [ssb] [ 214.333957] [] __device_release_driver+0x5a/0xb0 [ 214.333957] [] driver_detach+0x87/0x90 [ 214.333957] [] bus_remove_driver+0x6c/0xe0 [ 214.333957] [] driver_unregister+0x40/0x70 [ 214.333957] [] ssb_driver_unregister+0xb/0x10 [ssb] [ 214.333957] [] b43legacy_exit+0xd/0xf [b43legacy] [ 214.333957] [] sys_delete_module+0x14e/0x2b0 [ 214.333957] [] ? vfs_write+0xf7/0x150 [ 214.333957] [] ? tty_write_lock+0x50/0x50 [ 214.333957] [] ? sys_write+0x38/0x70 [ 214.333957] [] syscall_call+0x7/0xb [ 214.333957] Code: bc 27 00 00 00 00 a1 74 61 56 c1 55 89 e5 e8 a3 fc ff ff 5d c3 90 55 89 e5 57 56 89 c6 53 b8 40 ac 62 c1 83 ec 14 e8 bb b7 34 00 <8b> 46 4c 8d 50 01 85 c0 89 56 4c 75 03 83 0e 40 80 05 40 ac 62 [ 214.333957] EIP: [] drain_workqueue+0x15/0x170 SS:ESP 0068:cd767e5c [ 214.333957] CR2: 000000000000004c [ 214.341110] ---[ end trace c7e90ec026d875a6 ]---Index: wireless-testing/drivers/net/wireless/b43legacy/main.c The problem is fixed by making certain that the ucode pointer is not NULL before deregistering the driver in mac80211. Signed-off-by: Larry Finger Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/b43legacy/main.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/wireless/b43legacy/main.c +++ b/drivers/net/wireless/b43legacy/main.c @@ -3843,6 +3843,8 @@ static void b43legacy_remove(struct ssb_ cancel_work_sync(&wldev->restart_work); B43legacy_WARN_ON(!wl); + if (!wldev->fw.ucode) + return; /* NULL if fw never loaded */ if (wl->current_dev == wldev) ieee80211_unregister_hw(wl->hw);